Roy Keane has rejected the suggestion that Jose Mourinho could declare his first season as Manchester United manager a success if he lifts the Europa League title this month.

Mourinho has effectively given up on challenging for a top four finish in the Premier League and has admitted he is pinning his hopes of Champions League qualification on victory in the Europa League.

United are big favourites to book a place in the final of UEFA's second tier competition as they look to build on a 1-0 first leg lead against Celta Vigo in their semi-final tie at Old Trafford on Thursday night.

Yet Keane - who won seven Premier League titles during his time as United's midfield leader - was quick to dismiss the notion that Mourinho will be able to reflect on a successful season if he adds European success to the EFL Cup win he secured in February.

"For a club like Man United to win the League Cup and the Europa League, with the teams that are in it, you would expect them to do that," Keane told ITV Sport.

"He (Mourinho) has come up with plenty of excuses over the last few months, but there is no reason why United should shy away from dealing with these challenges.

"They are now sixth in the league, I think they are 19 points behind Chelsea. The manager and the players should be embarrassed by that.

"To be as far behind Chelsea as they are, it’s an embarrassment. With the squad they have and the players they have, the money they have spent, it’s not good enough."

Meanwhile, Keane believes Wayne Rooney needs to call time on his career at United, even though the club captain declared he was keen to stay at Old Trafford in a press conference on Thursday.

Rooney has become a back-up player for Mourinho at United this season and his former team-mate believes the time has come to end his 13-year career at United.

"If Wayne is going to stay at United for the next year or two and play 10 or 15 games as season, it’s no good to anyone," added Keane.

"Wayne needs to be playing regularly, to keep in shape and stay on top of his game. If he is going to be a bit part player at United then forget about it. He has got to move on."